At present, in an electric control system in which load needs to be frequently switched, thyristors (semi-controllable devices) are widely used to switch resistive, inductive, or capacitive load. To reduce driving power of a thyristor, a related technology used to reduce driving energy consumption emerges in the market, for example, a patent with Chinese Patent Application No. ZL201110430747.7 and entitled “TRIGGER POWER-SAVING APPARATUS AND THYRISTOR SWITCH”. A working principle disclosed by the patent is: A voltage detection circuit controls an electronic switch to be turned on when detecting that voltage at two ends of a main loop of a thyristor is greater than an on-state voltage (generally 1.1-1.9 V and defined as a conduction voltage drop in an original document) of the thyristor; a driving signal drives, by using the electronic switch, the thyristor to be turned on; and the voltage detection circuit controls the electronic switch to be turned off when detecting that the thyristor is turned on. Although the patent has a smaller driving dead zone compared with a conventional thyristor driving manner, the patent still has the following disadvantage: The voltage detection circuit controls the electronic switch to be turned on only when detecting that the voltage at the two ends of the main loop of the thyristor is greater than the on-state voltage of the thyristor. Because the driving signal of the thyristor is provided in a lagged manner, a driving dead zone objectively exists. In addition, there is a response time from obtaining, by the thyristor, the driving signal from a trigger of the thyristor to conduction output of the thyristor. Theoretically, the thyristor cannot be driven with no dead zone or with a smaller dead zone. Refer to a diagram of a waveform of the voltage at the two ends when the thyristor is turned on in this technology (as shown in FIG. 1).